1. Field of the Invention
The invention relates to connectors for portable objects such as credit cards or printed circuit cards.
2. Description of the Prior Art
A great variety of connectors are available for portable objects such as credit cards and printed circuit cards forming substrata for interconnection of electronic devices. As a rule, all these connectors essentially comprise elements incorporating a chamber which has an opening appropriate to receive a card along a predetermined direction and which contains a twin-jaw device for grasping the card by an "operating" edge, upon insertion of the card into the chamber.
The greater proportion of these connectors appertain to the group known as "sliding contact connectors", so called because their jaws are formed by flexible conductive contact blades in mutual confrontation which are spread apart from each other when the card is inserted. The jaws enclamp the operating edge of the card at the level of its output terminals. In this condition, the jaws are considered to be in their "operating position". An "idle position" is established when the card is absent or withdrawn.
It will be appreciated that such connectors are satisfactory for cards or substrata where the output terminals are contacts which are all distributed adjacent to and along the operating edge of the card and which have comparatively long conductors in the direction of manipulation of the card such that the connectors slide along the terminal conductors and immobilize the card they enclamp more satisfactorily, establish satisfactory electrical contacts with the output terminals of the card automatically provide a self-cleaning action on the terminals to the sliding of the contact blades of the jaws over the terminals when the card is received in the chamber, and prevent the contact blades from having to sweep over another surface of the card other than the output terminals so as to minimize the risk of being deleterious to the degree of wear of the blades and to the required quality of the electrical contacts.
The greater the extension of the output terminals of the card in the direction of manipulation of the card and/or the more powerful the gripping action engendered by the contact blades carried by the jaws of the connector, the more satisfactory is the connection. This is why if, as desirable and frequently required, the output terminals of a card cover no more than a small proportion of the surface of the card, the connector will require the application of a prohibitive and often intermittent force by a operator for inserting or withdrawing the card. Further, the number of operations will be restricted so that wear on the output terminals and contact blades caused by each operation is minimized and does not impair the quality of the electrical contacts.
As a pallative against these drawbacks, there has been developed a connector generally referred to as a ZIF (zero insertion force) connector. This connector is analogous to the sliding contact connector, but comprises a mechanism for opening and closing the jaws upon actuation by an operator. The operator secures the printed circuit card by first opening the jaws of the connector, thereafter freely inserting the card between the jaws (without force), and then closing the jaws on the card. To release the card, the jaws are again opened so that the cards may be withdrawn without any friction or sliding contact. Although the attrition and insertion force is eliminated by a ZIF connector, this connector requires the addition of an operating mechanism which renders it costlier and bulkier and, if the connector is placed at the unrestricted disposal of the public for the purpose of numerous operations, such as may be required at a remote banking terminal, there are imposed operating standards, measures for protection of the condition of the apparatus against any foreign substance (a self-cleaning action no longer applies) and measures to prevent mishandling or negligence on the part of the users. Means for verifying and indicating the authenticity of the connection established, i.e. that the jaws are properly closed and the correct circuit condition and connection of the proper electrical contacts established must also be provided.
Apart from these disadvantages which are inherent from the structure and use of such connectors, such connectors are specifically limited to the aforesaid type of printed circuit card and would be particularly inappropriate for printed circuit cards where the output terminals are contacts of small surface area, crowded into a rather small section of the card in the direction of but comparatively distant from the operating edge and, further, aligned in columns in the direction of handling of the card or at right angles thereto. On the one hand, the contact blades would be caused to sweep a surface of greater or lesser length of the card and would age and deteriorate very rapidly, and on the other hand, those blades which the card would encounter initially at the time of insertion would pass consecutively over the output terminals of each column which, from the electrical point of view, would require restrictive safety measures to prevent false readings.
Credit cards are normally fabricated to comply with standard specification ISO/DIS 2,894 promulgated by the International Standards Organization as noted in the aforementioned application of Badet et al, Ser. No. 4,588. These standard specifications require that a card of this kind should be rectangular, measuring 85.59.+-.0.12 mm.times.53.95.+-.0.06 mm and have a thickness of 0.76.+-.0.08 mm, to which it is permissible to add at most 0.50 mm, for example, for markings or layers which may indicate the name and address of the card holder. Such markings or layers may take the form of attached adhesive labels or they may be made by stamping of the card itself. According to the invention described in the aforesaid application Ser. No. 4,588, within a cavity of the card is housed an IC (integrated circuit) chip comprising a thin substrate equipped at one side with an integrated circuit device incorporating a memory and its controls for storing data showing debits, credits and the confidential code of the card holder and, at the other side, a plurality of contact segments intended to form the electrical output terminals of the card. An IC chip of a kind appropriate for a credit card of this nature is described, for example, in the aforenoted applications Ser. Nos. 69,252 and 69,253.
The advantage of a card of this kind consists in the ease of its manufacture attributable to the fact that the card may be made from a single sheet, that no more than one cavity need be formed in the same, and that the chip need merely be glued or welded after insertion into the cavity. Another advantage derives from the fact that the chip in which all the electrical circuits of the card are concentrated occupies a small surface of the card. Thus, a comparatively flexible card may be utilized, particularly if the chip is situated in a corner of the card.
As compared to the printed circuit card of known type hereinabove noted, the output terminals of a credit card of the kind described in the aforenoted patent applications Ser. Nos. 4,588, 69,252 and 69,253 are not aligned on one of its edges, but rather are concentrated in a section spaced apart form the edges. The output terminals are all situated on one and the same side of the card, they are preferably arranged in columns in the direction of the length or the width of the card on the score of ease of production and of connection to the conductors; and, because of the small permissible thickness of the card, the substratum of the IC chip is thin and comparatively flexible, which prevents any forcible contact between connector blades and output terminals of the card. Moreover, the credit card is an object commonly intended for a huge public and, in these circumstances, should be able to undergo a predetermined number of actions or transactions in the connectors without damage. The connectors, as a corollary, should be instruments which are robust, easy to use and reliable for a very great number of operations. It should be observed moreover, that more and more credit cards with incorporated integrated circuit devices will be employed in the future to allow processing these cards at remotely located terminals or connectors which may be portable themselves, to enable the holder of a card or a merchant to ascertain the balance of the user's account or at least to establish a credit check. Consequently, it is desirable for portable connectors to be robust, easy to use, light, of little bulk, inexpensive and as durable as possible.
Known attempts to produce connectors for credit cards include lever arrangments of the "compositor" type. A lever suspended at a fixed point of the connector element, comprises contact blades at its free extremity. The operator, upon inserting his card beneath the free extremity, pushes on the same to cause it to tip and thus to bring the blades in contact with the output terminals of the card. The lever is also commonly coupled to return means impelling it towards its idle position, as well as to locking means to stablize the same in one of its idle or operating positions. The return force frequently consists of the force of gravity, in which case the lever should be comparatively heavy and bulky and the connector installed at a permanent site. On the other hand, if the return force is provided by an element such as a spring, the addition of this element to the lever increases its bulk and fragility. Furthermore, the means of locking the lever in at least one of its idle and operating positions are added to the already substantial volume occupied by the lever, rendering the connector structure more complex and its application less easy.
The present invention fulfills the aforesaid requirements of fixed or portable connectors or terminals for credit cards and, in more general terms, it retains these same advantages for credit cards which may or may not be intended to be connected electrically, by means of, for example, a chip thereon to an associated electronic device. The portable connector, on the other hand, may simply cooperate with cards, notes or tickets, for the purpose of performing desired functions such as, for example, dating.